With increase in an aging population and change in the life environment, it is desired to develop an oral disintegrating-type solid preparation which can be easily taken, and can be handily and arbitrarily taken at any time anywhere without water, while maintaining convenient handling characteristics of tablets.
On the other hand, when a physiologically active substance is a substance exhibiting bitterness, from a viewpoint of drug taking observance, desirably, bitterness is masked by coating this substance. In addition, when a physiologically active substance is a substance liable to be degraded with an acid, it is necessary to coat the substance to prevent degradation by gastric acid and sufficiently deliver the substance to intestines. For these subjects, usually, coating tablets and capsules are used.
Although both are inconsistent requirements, as preparations which satisfy these requirements simultaneously, tablets comprising coated fine particles have been developed heretofore in the prior art. For example, JP 6-502194 A (U.S. Pat. No. 5,464,632) discloses a rapidly disintegrating multi-particle tablet characterized in that an effective substance is present in the form of coated fine particles and the like. Further, JP 2000-281564 A discloses an oral disintegrating tablet comprising coated fine particles in the tablet.
However, in the manufacture of a tablet comprising coated granules, there is a problem that, sometimes, a part of a coating film of the granules is ruptured during table compression, and there are problems that this decreases the aforementioned effect of masking bitterness, and reduces the acid resistance.